Undated-- Denny Hamlin suffered a compression fracture in his lower back during Sunday's last-lap crash at Fontana, Calif.

Joe Gibbs Racing disclosed the injury Monday and said Hamlin was expected to be released soon from a Southern California hospital to return home. He has what is called an L1 compression fracture; essentially, the first vertebra in the lumbar section of his spine collapsed.

There was no immediate word on how long his recovery would take.

Hamlin was hurt during a crash with Joey Logano at the end of Sunday's race. He complained of lower back pain afterward.

UPDATE 6: Rumors of Mark Martin's substitute role have been greatly exaggerated. It will now last only one race, after a series of conflicting announcements. Joe Gibbs Racing originally reported on Thursday that Martin would be competing for Denny Hamlin while Hamlin recuperates from a lower-back compression fracture, suffered during a last-lap crash at Auto Club Speedway on Sunday. The sub-headline that read, "Veteran NASCAR Driver Mark Martin to Drive No. 11 FedEx Toyota Until Hamlin Returns" indicated that the affable 54-year-old veteran would sub throughout Hamlin's recovery. But apparently the deal was not cleared by Aaron's, which is sponsoring Martin in the #55 this season and has enjoyed a relationship with Michael Waltrip since 2000.(Fox Sports)(3-30-2013)